Organizational Dysfunction

Schizophrenia
Schizophrenia is commonly described as a mental disorder in which a person becomes
detached from reality because of disruptions in the pattern of thinking and perception.
Although the etiology is not completely understood, it is closely related to dopaminergic
activity and is strongly associated with both neurocognitive and genetic elements of
executive dysfunction. Individuals with schizophrenia may demonstrate amnesia for
portions of their episodic memory. Observed damage to explicit, consciously accessed,
memory is generally attributed to the fragmented thoughts that characterize the
disorder. These fragmented thoughts are suggested to produce a similarly fragmented
organization in memory during encoding and storage, making retrieval more difficult.
However, implicit memory is generally preserved in patients with schizophrenia.
Patients with schizophrenia demonstrate spared performance on measures of visual
and verbal attention and concentration, as well as on immediate digit span recall,
suggesting that observed deficits cannot be attributed to deficits in attention or shortterm
memory. However, impaired performance was measured on psychometric
measures assumed to assess higher order executive function. Working memory and
multi-tasking impairments typically characterize the disorder. Persons with
schizophrenia also tend to demonstrate deficits in response inhibition and cognitive
flexibility.
Patients often demonstrate noticeable deficits in the central executive component of
working memory as conceptualized by Baddeley and Hitch. However, performance on
tasks associated with the phonological loop and visuospatial sketchpad are typically
less affected. More specifically, patients with schizophrenia show impairment to the
central executive component of working memory, specific to tasks in which the
visuospatial system is required for central executive control. The phonological system
appears to be more generally spared overall.
Attention Deficit Hyperactivity Disorder
A triad of core symptoms, namely inattention, hyperactivity, and impulsivity characterize
attention deficit/hyperactivity disorder. Individuals with ADHD often experience problems
with organization, discipline, and setting priorities, and these difficulties often persist
from childhood through adulthood. In both children and adults with ADHD, an underlying
executive dysfunction involving the prefrontal regions and other interconnected
subcortical structures has been found. As a result, people with ADHD commonly
perform more poorly than matched controls on interference control, mental flexibility and
verbal fluency. Also, a more central impairment in self-regulation is noted in cases of
ADHD. However, some research has suggested the possibility that the severity of
executive dysfunction in individuals with ADHD declines with age as they learn to
compensate for the aforementioned deficits. Thus, a decrease in executive dysfunction
in adults with ADHD as compared to children with ADHD is thought reflective of
compensatory strategies employed on behalf of the adults (e.g. using schedules to
organize tasks) rather than neurological differences.
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